Officers said on Thursday that they believe they have an “idea of their whereabouts” after they fled Chicago where they are suspected of murdering former hair stylist Trenton Cornell-Duranleau in Lathem’s apartment, the Press Association reported.

“Our primary focus is to facilitate a safe surrender and we strongly encourage Professor Lathem and Mr Warren to do the right thing,” a force spokesman added.

Officers say the victim, who lived in Chicago, was found with multiple stab wounds in the 10th floor apartment near the city centre at around 8.30pm on July 27 before being pronounced dead at the scene.

Court files give Warren’s address as the Oxford college but he says on Facebook that he lives in Swindon, Wiltshire, and is a former cashier and driver for Stagecoach.

Lathem has worked at Northwestern since 2007 and specialises in the bacteria that caused the bubonic plague.

Northwestern University said he has been placed on leave and is banned from entering the campus.